Thermoelectric element and thermoelectric module including the same

ABSTRACT

Disclosed herein are a thermoelectric element and a thermoelectric module including the same. The thermoelectric element is manufactured by differently setting diameter, density, and flatness, or laminating a plurality of sheets formed by mixing of metal or non-metal materials. Thus, thermoelectric figure of merit is improved in the thermoelectric module. Also, thermoelectric figure of merit, reliability, and efficiency of manufacturing process are improved in the thermoelectric module.

CROSS REFERENCE(S) TO RELATED APPLICATIONS

This application claims the benefit under 35 U.S.C. Section 119 ofKorean Patent Application Serial No. 10-2010-0125792, entitled“Thermoelectric Element and Thermoelectric Module Including The Same”filed on Dec. 9, 2010, which is hereby incorporated by reference in itsentirety into this application.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates to a thermoelectric element and athermoelectric module including the same, and more particularly, to athermoelectric element and a thermoelectric module capable of improvingthermoelectric figure of merits, and a thermoelectric module capable ofimproving the reliability and the efficiency of a manufacturing process.

2. Description of the Related Art

Due to the rapid increase in the use of fossil fuel energy, which hascaused global warming and energy depletion, the development of renewableenergy has been actively advanced over the world.

In addition to the development of renewable energy, many studies arebeing conducted in regard to a thermoelectric module capable ofutilizing energy efficiently.

Herein, the thermoelectric module may be used as a generator utilizingSeebeck effect in which electromotive force is generated when givingtemperature difference between both ends of a thermoelectric element, ora cooling and heating device using Peltier effect in which one endradiates heat and the other end absorbs heat when applying directcurrent to the thermoelectric element. As electronic components becomeminiaturized, highly power-consumed, highly integrated, and slimmedalong with remarkable growth of IT industries, it is necessary to coolvarious electronic devices like CPUs, etc., efficiently. In thissituation, thermoelectric elements are expected to be variouslyapplicable in the future because it has no noise and high coolingefficiency and it is capable of realizing local cooling and employingeco-friendly methods.

The thermoelectric module using such the thermoelectric elements mayinclude upper and lower electrodes, and thermoelectric elements disposedbetween the upper and lower electrodes. Herein, substrates forsupporting the thermoelectric elements are disposed on upper surfaces ofthe upper and lower electrodes, respectively. At this time, an aluminasubstrate having excellent electric insulating property is used for thesubstrates.

Meanwhile, the existing thermoelectric materials are mainly manufacturedby mechanical alloying where metal raw materials are mixed at a constantcomposition ratio. That is, basic processes such as initial dissolving,crushing and sintering are used for bulk type thermoelectric elements,into which dopants are injected to manufacture a P-type semiconductorand a N-type semiconductor.

Also, those of ordinary skill in the art tend to focus on development,such as micronization of thermoelectric power particles and improvementof sintering density, in order to enhance the thermoelectricperformance.

It has been focused on improving the thermoelectric figure of merit, zT,by utilizing superlattices or thermoelectric thin films lowdimensionalized through various deposition methods in a thin filmprocess, but remarkable success has not been shown so far. Therefore,technique development for improving the thermoelectric figure of meritis needed.

Meanwhile, the thermoelectric module includes a N-type semiconductor, aP-type semiconductor, metal electrodes of connecting between the twosemiconductors, and ceramic substrates, and these constitute the minimumunit, which is referred to as a single module.

In order to use the single module as a cooling or generating powerelement, it is necessary to generate charges in the N-type and P-typesemiconductors and then connect respective terminals to circuit throughelectrodes. Accordingly, in order to increase the efficiency of thesingle module, it is necessary to optimize the efficiency of respectiveparts constituting the module and the mutual efficiency between therespective parts in designing the single module.

However, as low conversion efficiency is required for the single moduleand high conversion efficiency is required in a field where thethermoelectric module is applicable, there is a rising interest on acomplex module using several single modules.

The existing complex module has been manufactured by repeatedlyconnecting single modules each having P-N constitution in seriesaccording to conditions of use. Respective single modules are connectedto each other by metal electrodes, and the metal electrodes areconnected to ceramic substrates. Since the respective single modules aredesigned to be in parallel with each other from a heat source, atemperature gradient of semiconductor materials itself from the heatsource is the same as that of the single modules. This existing serialtype module structure has problems with respect to short circuits andfatal disadvantages in that the entire complex module dose not operateif any one of single modules is broken. Also, this serial type modulehas a high level of dependence on voltage.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a thermoelectricelement capable of improving the thermoelectric figure of merits.

Another object of the present invention is to provide a thermoelectricmodule capable of improving the thermoelectric figure of merits and athermoelectric module capable of improving the reliability and themanufacturing efficiency.

According to an exemplary embodiment of the present invention, there isprovided a thermoelectric element formed by laminating a plurality ofsemiconductor layers. The semiconductor layers are, respectively, formedof at least two kinds of thermoelectric semiconductor materials whichare different from each other in at least one of diameter, density andflatness.

According to another exemplary embodiment of the present invention,there is provided a thermoelectric element, including: firstsemiconductor layers formed of thermoelectric semiconductor materials;and second semiconductor layers formed of thermoelectric semiconductormaterials which are different from the materials forming the firstsemiconductor layers in at least one of diameter, density and flatness.

Preferably, the first semiconductor layers and the second semiconductorlayers are alternately laminated.

The first semiconductor layers and the second semiconductor layers maybe alternately laminated to constitute a structure of at least threelayers.

Preferably, the diameter of the materials forming the secondsemiconductor layers may be more than 1.5 times the diameter of thematerials forming the first semiconductor layers.

Preferably, the diameter of the materials forming the firstsemiconductor layers may be about 10 nm to about 900 μm.

The density of the second semiconductor layers may be more than 1.5times the density of the first semiconductor layers to distinguish thelayers.

The rate between minor axis/major axis ratio of the materials formingthe first semiconductor layers and minor axis/major axis ratio of thematerials forming the second semiconductor layers may be in the range of1:0.1 to 0.9, to distinguish the layers.

The diameter of the materials forming the first semiconductor layers maybe divided into at least two kinds of values.

The diameter of the materials forming the second semiconductor layersmay be divided into at least two kinds of values.

According to another exemplary embodiment of the present invention,there is provided a thermoelectric element, including: firstthermoelectric layers formed of thermoelectric semiconductor materials;and second thermoelectric layers each formed by combining a regionformed of thermoelectric semiconductor materials and a region formed ofmetal materials.

Preferably, the first thermoelectric layers and the secondthermoelectric layers may be alternately laminated.

Preferably, the first thermoelectric layers and the secondthermoelectric layers may be alternately laminated to constitute astructure of at least three layers.

Preferably, the region formed of the thermoelectric semiconductormaterials and the region formed of the metal materials may be positioneddifferently in each of the second thermoelectric layers whenever thesecond thermoelectric layers are disposed in different layer levels.

Preferably, the diameter of the thermoelectric semiconductor materialsforming the first thermoelectric layers may be different from thediameter of the thermoelectric semiconductor materials forming thesecond thermoelectric layers.

Preferably, the diameter of the materials forming the firstsemiconductor layers may be divided into at least two kinds of values.

Preferably, the diameter of the materials forming the secondsemiconductor layers may be divided into at least two kinds of values.

According to another exemplary embodiment of the present invention,there is provided a thermoelectric element, including: semiconductorlayers formed of thermoelectric semiconductor material; and complexsemiconductor layers each formed by mixing thermoelectric semiconductormaterials having a different diameter from the materials forming thesemiconductor layers and non-semiconductor materials.

The diameter of the materials forming the semiconductor layers may bedivided into at least two kinds of values.

The diameter of the materials forming the complex semiconductor layersmay be divided into at least two kinds of values.

Preferably, the semiconductor layers and the complex semiconductorlayers may be alternately laminated.

Preferably, the semiconductor layers and the complex semiconductorlayers may be alternately laminated to constitute a structure of atleast three layers.

Preferably, the diameter of the materials forming the semiconductorlayers may be about 10 nm to about 900 μm.

According to another exemplary embodiment of the present invention,there is provided a thermoelectric module including the thermoelectricelements.

The thermoelectric module may further include first and secondelectrodes facing each other. The thermoelectric elements may haveP-type in one single mode and may be interposed between the first andsecond electrodes.

The thermoelectric module may further include first and secondelectrodes facing each other. The thermoelectric elements may haveN-type in one single mode and may be interposed between the first andsecond electrodes.

The thermoelectric module may further include upper and lower substrateseach having one surface on which a plurality of concave portions areformed. The thermoelectric elements may have P-type in one single modeand may be interposed between the upper and lower substrates.

The thermoelectric module may further include upper and lower substrateseach having one surface on which a plurality of concave portions areformed. The thermoelectric elements may have N-type in one single modeand may be interposed between the upper and lower substrates.

The upper and lower substrates may be insulating substrates, and aconductive material may be coated on the surface of each of the upperand lower substrates which has the concave portions.

According to another exemplary embodiment of the present invention,there is provided a thermoelectric module, including: first and secondelectrodes facing each other; and a plurality of thermoelectric elementsinterposed between the first and second electrodes. The thermoelectricelements have any one of N-type and P-type in one single mode.

According to another exemplary embodiment of the present invention,there is provided a thermoelectric module, including: upper and lowersubstrates each having one surface on which a plurality of concaveportions are formed; and thermoelectric elements each interposed betweenthe upper and lower substrates by being partially inserted into theconcave portions.

The upper and lower substrates may be insulating substrates, and aconductive material may be coated on the surface of each of the upperand lower substrates which has the concave portions.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other aspects, features and other advantages of thepresent invention will be more clearly understood from the followingdetailed description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a perspective view showing a structure of a generalthermoelectric module;

FIG. 2 is a cross-sectional view showing a structure of a thermoelectricelement according to a first exemplary embodiment of the presentinvention;

FIG. 3 is a cross-sectional view showing a structure of a thermoelectricelement according to a second exemplary embodiment of the presentinvention;

FIG. 4 is a cross-sectional view showing a structure of a thermoelectricelement according to a third exemplary embodiment of the presentinvention;

FIG. 5 is a cross-sectional view showing a structure of a thermoelectricelement according to a fourth exemplary embodiment of the presentinvention;

FIG. 6 is a cross-sectional view showing a structure of a thermoelectricelement according to a fifth exemplary embodiment of the presentinvention;

FIG. 7 is a cross-sectional view showing a structure of a thermoelectricelement according to a sixth exemplary embodiment of the presentinvention;

FIG. 8 is a cross-sectional view showing a structure of a thermoelectricelement according to a seventh exemplary embodiment of the presentinvention;

FIG. 9 is a perspective view showing a structure of a thermoelectricmodule according to a ninth exemplary embodiment of the presentinvention; and

FIG. 10 is a perspective view showing a structure of a thermoelectricmodule according to a tenth exemplary embodiment of the presentinvention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Various advantages and features of the present invention and methodsaccomplishing thereof will become apparent from the followingdescription of embodiments with reference to the accompanying drawings.However, the present invention may be modified in many different formsand it should not be limited to the embodiments set forth herein. Theseembodiments may be provided so that this disclosure will be thorough andcomplete, and will fully convey the scope of the invention to thoseskilled in the art. Like reference numerals in the drawings denote likeelements.

Terms used in the present specification are for explaining theembodiments rather than limiting the present invention. Unlessexplicitly described to the contrary, a singular form includes a pluralform in the present specification. The word “comprise” and variationssuch as “comprises” or “comprising,” will be understood to imply theinclusion of stated constituents, steps, operations and/or elements butnot the exclusion of any other constituents, steps, operations and/orelements.

Hereinafter, structures and operations of the present invention will bedescribed in detail with reference to the accompanying drawings.

FIG. 1 shows a structure of a thermoelectric module, excluding a powersupply unit. Generally, N-type and P-type semiconductors are used for athermoelectric element 100. The module is formed by arranging the N-typeand P-type semiconductors, which make plural pairs, on a plane and thenconnecting the semiconductors in series using metal electrodes. Whencurrent is applied to the module, carriers, that is, electrons (e−) andholes (h+), are generated in one side of the metal electrodes. Theelectrons and the holes flow to the n-type semiconductors and the p-typeconductors, respectively, with transferring heat. These carriers arerecombined in the opposite side of the metal electrodes.

Meanwhile, the thermoelectric figure of merit of the generalthermoelectric element 100 is defined in Equation 1:

$\begin{matrix}{{zT} = {\frac{\alpha^{2}\sigma}{k}T}} & \left\lbrack {{Equation}\mspace{14mu} 1} \right\rbrack\end{matrix}$

wherein, zT is thermoelectric figure of merit, α is Seebeck coefficient,σ is electrical conductivity, k is thermal conductivity, and T meanstemperature.

As represented in Equation 1, the thermal conductivity and theelectrical conductivity have interrelation therebetween. In addition,electrons transfer heat and electricity together and phonons are mediaof transferring heat.

As shown in Equation 1, the electric conductivity and the thermalconductivity have an inverse relationship therebetween. Accordingly, inorder to improve the thermoelectric figure of merit (zT), it is neededto increase the scattering of phonons while raising the electricconductivity by moving electrons appropriately from one end to theopposite end in the thermoelectric element 100.

The thermoelectric element 100 set forth in the present invention mayhave a layered structure in various manners. The scattering of phononsis increased at boundary parts between respective layers and throughoutthe entire of the thermoelectric element 100. As a result, the object ofimproving the thermoelectric figure of merit (zT) is accomplished.

Inventors of the present invention invented techniques of forming thethermoelectric element 100 by laminating layers having differentphysical properties, as a result of repeated studies on structurescapable of improving the scattering of phonons as above.

That is, different physical properties are imparted to the layers of thethermoelectric element 100, by laminating plural semiconductor layersrespectively formed of at least two kinds of thermoelectricsemiconductor materials which are different from each other in at leastone of diameter, density, and flatness, by using a sheet including aregion formed of thermoelectric semiconductor materials and a regionformed of metal materials, or by adding non-semiconductor materials inspecific layers.

Hereafter, constitutions according to respective exemplary embodimentsof the present invention will be described in detail with reference tothe accompanying drawings.

Example 1

FIG. 2 shows a structure of a thermoelectric element 100 according to afirst exemplary embodiment of the present invention.

Referring to FIG. 2, the thermoelectric element 100 may include: firstsemiconductor layers 110 formed of thermoelectric semiconductormaterials; and second semiconductor layers 120 formed of semiconductormaterials having a different diameter from the materials forming thefirst semiconductor layer 110.

At this time, the first semiconductor layers 110 and the secondsemiconductor layers 120 may be alternately laminated to maximize thedifference of physical property at the interface between the layers. Thefirst and second semiconductor layers may be laminated in three or morelayers.

Also, it is preferable that the diameter of the materials forming thesecond semiconductor layers 120 is more than 5 times the diameter of thematerials forming the first semiconductor layers 110, considering theinterface effect due to the difference of physical property. If thedifference of diameter between the materials forming the firstsemiconductor layers 110 and the materials forming the secondsemiconductor layers 120 is too small, the interface effect is not largesuch that the scattering of phonons is increased slightly, therebymaking it impossible to accomplish the intended object.

The diameter of the materials forming the first semiconductor layers 110is, preferably, about 10 nm to about 900 μm.

Example 2

FIG. 3 shows a structure of a thermoelectric element 100 according to asecond exemplary embodiment of the present invention.

Referring to FIG. 3, the thermoelectric element 100 may include: firstsemiconductor layers 110 formed of thermoelectric semiconductormaterials; and second semiconductor layers 120 formed of semiconductormaterials which make the second semiconductor layers 120 have adifferent density from the first semiconductor layers 110.

At this time, it is preferable that the density of the secondsemiconductor layers 120 is more than 1.5 times the density of the firstsemiconductor layers 110, in order to increase the scattering of phononsdue to the interface effect between layers efficiently. If thedifference of density is too small, the interface effect is not largesuch that the scattering of phonons is increased slightly, therebymaking it impossible to accomplish the intended object.

Also, the first semiconductor layers 110 and the second semiconductorlayers 120 may be alternately laminated to maximize the difference ofphysical property at the interface between the layers. The first andsecond semiconductor layers may be laminated in three or more layers.

Example 3

FIG. 4 shows a structure of a thermoelectric element 100 according to athird exemplary embodiment of the present invention.

Referring to FIG. 4, the thermoelectric element 100 may include: firstsemiconductor layers 110 formed of thermoelectric semiconductormaterials; and second semiconductor layers 120 formed of thermoelectricsemiconductor materials having a different flatness from the materialsforming the first semiconductor layers 110.

The flatness may be numerically expressed by a ratio of major axis andminor axis of a particle.

In other words, if the minor axis/major axis ratio of the materialsforming the first semiconductor layers 110 is different from the minoraxis/major axis ratio of the materials forming the second semiconductorlayers 120, the scattering of phonons can be increased at the interfacebetween the two layers.

Herein, the rate of the minor axis/major axis ratio between the firstsemiconductor layers 110 and the second semiconductor layers 120 may beset in a range of 1:0.1 to 0.9, to maximize the scattering of phonons atthe interface between the layers.

Also, the first semiconductor layers 110 and the second semiconductorlayer 120 may be alternately laminated to maximize the difference ofphysical property at the interface between the layers. The first andsecond semiconductor layers may be laminated in three or more layers.

Example 4

FIG. 5 shows a structure of a thermoelectric element according to afourth exemplary embodiment of the present invention.

Referring to FIG. 5, the diameter of the materials forming the firstsemiconductor layers 110 or the diameter of the materials forming thesecond semiconductor layers 120 may be divided into at least two kindsof values to increase the scattering of phonons more.

In other words, if the first semiconductor layers 100 are composed ofparticles having different diameters and the second semiconductor layers120 are composed of particles having the same diameter, the physicalproperty is changed at the interface between the first semiconductorlayers 110 and the second semiconductor layers 120, thereby increasingthe scattering of phonons.

Example 5

FIG. 6 shows a structure of a thermoelectric element 100 according to afifth exemplary embodiment of the present invention.

Referring to FIG. 6, the thermoelectric element 100 may include: firstthermoelectric layers 130 formed of thermoelectric semiconductormaterials; and second thermoelectric layers 140 each formed by combininga region 141 formed of thermoelectric semiconductor materials and aregion 142 formed of metal materials.

Herein, the materials suitable for use as the metal materials may be,but not limited to Cu, Ag, Ni, Pd, Al, B, and so on.

Preferably, the first thermoelectric layers 130 and the secondthermoelectric layers 140 may be alternately laminated, and may belaminated in three or more layers.

Herein, if the region 141 formed of the thermoelectric semiconductormaterials and the region 142 formed of the metal materials arepositioned differently in each of the second thermoelectric layers 140whenever the second thermoelectric layers 140 are disposed in differentlayer levels, the scattering of phonons can be more increased.

Example 6

FIG. 7 shows a structure of a thermoelectric element 100 according to asixth exemplary embodiment of the present invention.

Referring to FIG. 7, when the diameter of the thermoelectricsemiconductor materials forming the first thermoelectric layers 130 isset differently from the diameter of the thermoelectric semiconductormaterials forming the second thermoelectric layers 140, the scatteringof phonons can be increased at the interface between the two layers.

In addition, as shown in FIG. 5 and the fourth exemplary embodiment,when the diameter of the materials forming the first thermoelectriclayers 130 or the diameter of the materials forming the secondthermoelectric layers 140 is divided into at least two kinds of values,the scattering of phonons can be more increased.

Example 7

FIG. 8 shows a structure of a thermoelectric element 100 according to aseventh exemplary embodiment of the present invention.

Referring to FIG. 8, the thermoelectric element 100 may include:semiconductor layers 150 formed of thermoelectric semiconductormaterials; and complex semiconductor layers 160 each formed by mixingsemiconductor materials having a different diameter from the materialsforming the semiconductor layers 150 and non-semiconductor materials.

The non-semiconductor materials contained in the complex semiconductorlayers 160 are capable of inducing the scattering of phonons, and also,increasing the scattering of phonons at the interface between thesemiconductor layers 150 and the complex semiconductor layers 160.

Herein, the diameter of the materials forming the semiconductor layers150 may be divided into at least two kinds of values, and the diameterof the materials forming the complex semiconductor layers 160 may bedivided into at least two kinds of values.

Preferably, the semiconductor layers 150 and the complex semiconductorlayers 160 may be alternately laminated, and may be laminated in threeor more layers.

Also, the diameter of the materials forming the semiconductor layers 150is preferably about 10 nm to about 900 μm.

Also, the diameter of the materials forming the semiconductor layers orthe complex semiconductor layers may be divided into at least two kindsof sizes.

Example 8

Although not shown in the figures, a thermoelectric module according toan eighth exemplary embodiment of the present invention may include thethermoelectric elements 100 mentioned in the first to seventh exemplaryembodiments.

Example 9

FIG. 9 shows a structure of a thermoelectric module according to a ninthexemplary embodiment of the present invention.

Referring to FIG. 9, the thermoelectric module according to the presentinvention may include a first electrode 210 and a second electrode 220facing each other. Thermoelectric elements 100, which have P-type orN-type in one single mode, are interposed between the first electrode210 and the second electrode 220.

The above constitution allows skipping the formation of complicateelectrode patterns, compared with the existing serial typethermoelectric module, thereby improving the efficiency of manufacturingprocess. Also, since the thermoelectric performance is realized throughnormal thermoelectric elements 100 even though some of pluralthermoelectric elements 100 have problems, the reliability is improved.

Example 10

FIG. 10 shows a structure of a thermoelectric module according to atenth exemplary embodiment of the present invention.

Referring to FIG. 10, the thermoelectric module according to the presentinvention may include an upper substrate 310 and a lower substrate 320each having one surface on which a plurality of concave portions 311 areformed. The thermoelectric elements 100 may be interposed between theupper substrate 310 and the lower substrate 320.

Herein, the substrates 310 and 320 may be formed of conductivematerials.

When the substrates 310 and 320 are formed of insulating materials, itis preferable that electrodes are formed in the concave portions 311 ofthe substrates 310 and 320 using conductive materials and the electrodesare connected electrically.

Also, a single mode of P-type or N-type thermoelectric elements 100 maybe interposed between the conductive substrates or between theelectrodes to improve the reliability of the thermoelectric module.

Also, the P-type and N-type thermoelectric elements 100 may be disposedin series. In this case, the electrodes are also arranged in seriesaccording to arrangement of the thermoelectric elements 100, such thatthe entire module is constituted in series.

The above constitution can improve the efficiency in an assemblingprocess of connecting the thermoelectric elements 100 to the substratesor the electrodes, thereby reducing the manufacturing time and themanufacturing costs.

The thermoelectric semiconductor materials may be P-type semiconductormaterials or N-type semiconductor materials.

In addition, the thermoelectric semiconductor materials may be composedof a mixture of Bi (bismuth) and Te (tellurium).

Also, the thermoelectric semiconductor materials may be composed ofZn_(x)Sb_(y), wherein x/y is 0.5 to 1.5, and especially, Zn₄Sb₃ (x=4,y=3) may be used.

Also, the thermoelectric semiconductor materials may be composed ofCo_(x)Sb_(y), wherein x/y is 0.1 to 2.0, and especially, CoSb₃ (x=1,y=3) may be used.

As set forth above, the thermoelectric element and the thermoelectricmodule according to the present invention are capable of improving thethermoelectric figure of merit by inducing the scattering of phononsactively at the boundary portion between respective layers.

Also, according to the present invention, a plurality of single-typethermoelectric elements are connected in parallel to improve thereliability compared with the existing serial connection structure. Thepresent invention is capable of simplifying the electrode structure andthe assembling procedure to improve the efficiency of the manufacturingprocess of the thermoelectric module.

Also, the present invention is capable of improving the assemblingprocess of the thermoelectric module using substrates having concaveportions to reduce the manufacturing time and the manufacturing costs.

The present invention has been described in connection with what ispresently considered to be practical exemplary embodiments. Although theexemplary embodiments of the present invention have been described, thepresent invention may be also used in various other combinations,modifications and environments. In other words, the present inventionmay be changed or modified within the range of concept of the inventiondisclosed in the specification, the range equivalent to the disclosureand/or the range of the technology or knowledge in the field to whichthe present invention pertains. The exemplary embodiments describedabove have been provided to explain the best state in carrying out thepresent invention. Therefore, they may be carried out in other statesknown to the field to which the present invention pertains in usingother inventions such as the present invention and also be modified invarious forms required in specific application fields and usages of theinvention. Therefore, it is to be understood that the invention is notlimited to the disclosed embodiments. It is to be understood that otherembodiments are also included within the spirit and scope of theappended claims.

1. A thermoelectric element formed by laminating a plurality ofsemiconductor layers, wherein the semiconductor layers are,respectively, formed of at least two kinds of thermoelectricsemiconductor materials which are different from each other in at leastone of diameter, density and flatness.
 2. A thermoelectric element,comprising: first semiconductor layers formed of thermoelectricsemiconductor materials; and second semiconductor layers formed ofthermoelectric semiconductor materials which are different from thematerials forming the first semiconductor layers in at least one ofdiameter, density and flatness.
 3. The thermoelectric element accordingto claim 2, wherein the first semiconductor layers and the secondsemiconductor layers are alternately laminated.
 4. The thermoelectricelement according to claim 2, wherein the first semiconductor layers andthe second semiconductor layers are alternately laminated to constitutea structure of at least three layers.
 5. The thermoelectric elementaccording to claim 2, wherein the diameter of the materials forming thesecond semiconductor layers is more than 1.5 times the diameter of thematerials forming the first semiconductor layers.
 6. The thermoelectricelement according to claim 2, wherein the diameter of the materialsforming the first semiconductor layers is about 10 nm to about 900□. 7.The thermoelectric element according to claim 2, wherein the density ofthe second semiconductor layers is more than 1.5 times the density ofthe first semiconductor layers.
 8. The thermoelectric element accordingto claim 2, wherein the rate between minor axis/major axis ratio of thematerials forming the first semiconductor layers and minor axis/majoraxis ratio of the materials forming the second semiconductor layers isin the range of 1:0.1 to 0.9.
 9. The thermoelectric element according toclaim 2, wherein the diameter of the materials forming the firstsemiconductor layers is divided into at least two kinds of values. 10.The thermoelectric element according to claim 2, wherein the diameter ofthe materials forming the second semiconductor layers is divided into atleast two kinds of values.
 11. A thermoelectric element, comprising:first thermoelectric layers formed of thermoelectric semiconductormaterials; and second thermoelectric layers each formed by combining aregion formed of thermoelectric semiconductor materials and a regionformed of metal materials.
 12. The thermoelectric element according toclaim 11, wherein the first thermoelectric layers and the secondthermoelectric layers are alternately laminated.
 13. The thermoelectricelement according to claim 11, wherein the first thermoelectric layersand the second thermoelectric layers are alternately laminated toconstitute a structure of at least three layers.
 14. The thermoelectricelement according to claim 11, wherein the region formed of thethermoelectric semiconductor materials and the region formed of themetal materials are positioned differently in each of the secondthermoelectric layers whenever the second thermoelectric layers aredisposed in different layer levels.
 15. The thermoelectric elementaccording to claim 11, wherein the diameter of the thermoelectricsemiconductor materials forming the first thermoelectric layers isdifferent from the diameter of the thermoelectric semiconductormaterials forming the second thermoelectric layers.
 16. Thethermoelectric element according to claim 11, wherein the diameter ofthe materials forming the first semiconductor layers is divided into atleast two kinds of values.
 17. The thermoelectric element according toclaim 10, wherein the diameter of the materials forming the secondsemiconductor layers is divided into at least two kinds of values.
 18. Athermoelectric element, comprising: semiconductor layers formed ofthermoelectric semiconductor materials; and complex semiconductor layerseach formed by mixing thermoelectric semiconductor materials having adifferent diameter from the materials forming the semiconductor layersand non-semiconductor materials.
 19. The thermoelectric elementaccording to claim 18, wherein the diameter of the materials forming thesemiconductor layers is divided into at least two kinds of values. 20.The thermoelectric element according to claim 18, wherein the diameterof the materials forming the complex semiconductor layers is dividedinto at least two kinds of values.
 21. The thermoelectric elementaccording to claim 18, wherein the semiconductor layers and the complexsemiconductor layers are alternately laminated.
 22. The thermoelectricelement according to claim 18, wherein the semiconductor layers and thecomplex semiconductor layers are alternately laminated to constitute astructure of at least three layers.
 23. The thermoelectric elementaccording to claim 18, wherein the diameter of the materials forming thesemiconductor layers is about 10 nm to about 900 um.
 24. Athermoelectric module comprising thermoelectric elements according toclaims 1, 2, 11 or
 18. 25. The thermoelectric module according to claim24, further comprising first and second electrodes facing each other,wherein the thermoelectric elements have P-type in one single mode andare interposed between the first and second electrodes.
 26. Thethermoelectric module according to claim 24, further comprising firstand second electrodes facing each other, wherein the thermoelectricelements have N-type in one single mode and are interposed between thefirst and second electrodes.
 27. The thermoelectric module according toclaim 24, further comprising upper and lower substrates each having onesurface on which a plurality of concave portions are formed, wherein thethermoelectric elements have P-type in one single mode and areinterposed between the upper and lower substrates.
 28. Thethermoelectric module according to claim 25, further comprising upperand lower substrates each having one surface on which a plurality ofconcave portions are formed, wherein the thermoelectric elements haveN-type in one single mode and are interposed between the upper and lowersubstrates.
 29. The thermoelectric module according to claim 27 or 28,wherein each of the upper and lower substrates is an insulatingsubstrate, and a conductive material is coated on the surface of each ofthe upper and lower substrates which has the concave portions.
 30. Athermoelectric module, comprising: first and second electrodes facingeach other; and a plurality of thermoelectric elements interposedbetween the first and second electrodes, the thermoelectric elementsbeing any one of N-type and P-type in one single mode.
 31. Athermoelectric module, comprising: upper and lower substrates eachhaving one surface on which a plurality of concave portions are formed;and thermoelectric elements each interposed between the upper and lowersubstrates by being partially inserted into the concave portions. 32.The thermoelectric module according to claim 31, wherein each of theupper and lower substrates is an insulating substrate, and a conductivematerial is coated on the surface of each of the upper and lowersubstrates which has the concave portions.